package edu.princeton;

/*************************************************************************
 *  Compilation:  javac StdIn.java
 *  Execution:    java StdIn
 *
 *  Reads in data of various types from standard input.
 *
 *************************************************************************/

import java.io.BufferedInputStream;
import java.util.Locale;
import java.util.Scanner;

/**
 * <i>Standard input</i>. This class provides methods for reading strings and
 * numbers from standard input.
 * <p>
 * The Locale used is: language = English, country = US. This is consistent with
 * the formatting conventions with Java floating-point literals, command-line
 * arguments (via <tt>Double.parseDouble()</tt>) and standard output (via
 * <tt>System.out.print()</tt>). It ensures that standard input works with the
 * input files used in the textbook.
 * <p>
 * For additional documentation, see <a
 * href="http://introcs.cs.princeton.edu/15inout">Section 1.5</a> of
 * <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> by
 * Robert Sedgewick and Kevin Wayne.
 */
public final class StdIn {

	// assume Unicode UTF-8 encoding
	private static String charsetName = "UTF-8";

	// assume language = English, country = US for consistency with System.out.
	private static Locale usLocale = new Locale("en", "US");

	// the scanner object
	private static Scanner scanner = new Scanner(new BufferedInputStream(System.in), charsetName);

	// static initializer
	static {
		scanner.useLocale(usLocale);
	}

	// singleton pattern - can't instantiate
	private StdIn() {
	}

	/**
	 * Is there only whitespace left on standard input?
	 */
	public static boolean isEmpty() {
		return !scanner.hasNext();
	}

	/**
	 * Return next string from standard input
	 */
	public static String readString() {
		return scanner.next();
	}

	/**
	 * Return next int from standard input
	 */
	public static int readInt() {
		return scanner.nextInt();
	}

	/**
	 * Return next double from standard input
	 */
	public static double readDouble() {
		return scanner.nextDouble();
	}

	/**
	 * Return next float from standard input
	 */
	public static float readFloat() {
		return scanner.nextFloat();
	}

	/**
	 * Return next short from standard input
	 */
	public static short readShort() {
		return scanner.nextShort();
	}

	/**
	 * Return next long from standard input
	 */
	public static long readLong() {
		return scanner.nextLong();
	}

	/**
	 * Return next byte from standard input
	 */
	public static byte readByte() {
		return scanner.nextByte();
	}

	/**
	 * Return next boolean from standard input, allowing "true" or "1" for true,
	 * and "false" or "0" for false
	 */
	public static boolean readBoolean() {
		String s = readString();
		if (s.equalsIgnoreCase("true"))
			return true;
		if (s.equalsIgnoreCase("false"))
			return false;
		if (s.equals("1"))
			return true;
		if (s.equals("0"))
			return false;
		throw new java.util.InputMismatchException();
	}

	/**
	 * Does standard input have a next line?
	 */
	public static boolean hasNextLine() {
		return scanner.hasNextLine();
	}

	/**
	 * Return rest of line from standard input
	 */
	public static String readLine() {
		return scanner.nextLine();
	}

	/**
	 * Return next char from standard input
	 */
	// a complete hack and inefficient - email me if you have a better
	public static char readChar() {
		// (?s) for DOTALL mode so . matches a line termination character
		// 1 says look only one character ahead
		// consider precompiling the pattern
		String s = scanner.findWithinHorizon("(?s).", 1);
		return s.charAt(0);
	}

	/**
	 * Return rest of input from standard input
	 */
	public static String readAll() {
		if (!scanner.hasNextLine())
			return null;

		// reference:
		// http://weblogs.java.net/blog/pat/archive/2004/10/stupid_scanner_1.html
		return scanner.useDelimiter("\\A").next();
	}

	/**
	 * Read rest of input as array of ints
	 */
	public static int[] readInts() {
		String[] fields = readAll().trim().split("\\s+");
		int[] vals = new int[fields.length];
		for (int i = 0; i < fields.length; i++)
			vals[i] = Integer.parseInt(fields[i]);
		return vals;
	}

	/**
	 * Read rest of input as array of doubles
	 */
	public static double[] readDoubles() {
		String[] fields = readAll().trim().split("\\s+");
		double[] vals = new double[fields.length];
		for (int i = 0; i < fields.length; i++)
			vals[i] = Double.parseDouble(fields[i]);
		return vals;
	}

	/**
	 * Read rest of input as array of strings
	 */
	public static String[] readStrings() {
		String[] fields = readAll().trim().split("\\s+");
		return fields;
	}

	/**
	 * Unit test
	 */
	public static void main(String[] args) {

		System.out.println("Type a string: ");
		String s = StdIn.readString();
		System.out.println("Your string was: " + s);
		System.out.println();

		System.out.println("Type an int: ");
		int a = StdIn.readInt();
		System.out.println("Your int was: " + a);
		System.out.println();

		System.out.println("Type a boolean: ");
		boolean b = StdIn.readBoolean();
		System.out.println("Your boolean was: " + b);
		System.out.println();

		System.out.println("Type a double: ");
		double c = StdIn.readDouble();
		System.out.println("Your double was: " + c);
		System.out.println();

	}

}
